A corpora



Reissued June 14, 1927.

UNITED STATES HARRY M. NAUGLE AND ARTHUR J". TOWNSEND, OF CANTON, OHIO,ASSIGNORS TO FORGED STEEL WHEEL COMPANY, OF PITTSBURGH, PENNSYLVANIA, ACORPORA- TION OF PENNSYLVANIA. I

METHOD OF MAKING STRIP SHEETS.

Io Drawing. Original No. 1,586,028, dated April 28 1925, Serial No.583,612, flied August 22, 1922.

Application i'or reissue filed April 25, 1927. Serial 11'0. 186,559, I

1200 to 1400 F., preferably 1300 F., in a The invention relates to theproduction of metal strip sheets, for use in making deep drawn or formedproducts; and the object of the improvement is to give the sheets thenecessary high ductility required for the drawing or forming operations,by a simple, direct, efi'ec'tive and economical method.

It is desirable, if not necessary, to make such strip sheets from anordinary strip, skelp or bar, by a longitudinal rolling operation. A hotrolling reduction does not produce the necessary or. desirable quality,surface, or accuracy to gauge; while a cold rolling operation hasheretofore only been used to reduce the material to about one-third ofits original thickness, without an intermediate annealing. v

' The present method involves the production of a strip sheet havinghigh ductility, as

well as the desired quality, surface and accuracy to gauge, for thepurpose intended, by first reducing the material rapidly, by a smallnumber of heavy drafts or passes between cold rolls, to say half or lessthan half of the original thickness of the metal followed by a quickannealingof the individual strip sheets which have been rapidly reducedby the cold rolling operation. a

A readjustment of the grains to relieve them of the strains produced bythe rapid cold rolling reduction, cannot be accomplished by the ordinarybox annealing of a mass of material, for the reason that the long periodof time required to properly heat the inner portions of the mass, notonly re sults in an over-annealing of the outer portion thereof, but inthe production of a grain growth in a considerable portion of the mass,which destroys the ductility, and the uniformity, and also decreases thestren th'of the material intheouter portion of the carge.

An open or a continuous method of quickly annealing individual sheets,however, no only prevents a growth of the rains, but accomplishes areadjustment of t e grains into a uniform structure with fine grainsthroughout, and gives to the strip sheet the necessary high ductility,in additionv to the desired quality, surface and accuracy of gauge,which has been given to them by the cold rolling reduction. The bestresults have been obtained by an open annealing of individual sheets ata temperature of from from a strip, skelp, bar or the like, which Re.16,652 PATENT OFFICE.

cycle of fortyminutes or less. When, however, a very thin stripisannealed by passing it continuously through a heating tube or tunnel,a much higher temperature may be.

employed and the time may be shortened to as low as a cycle of fiveminutes.

It will be understod that steel strips are usually one-fourth'of an inchor under in thickness, that skelp runs from one-sixteenth tothree-eighths of an inch in thickness, and that bars run from one-fourthof an inch and upward in thickness; and it has been found-that the samecan be reduced to from fifty to sixty per cent less than'the originalthickness by from four to ten passes between cold rolls, depending uponthe original thickness of the material.

We claim 1. The method of making a strip sheet from a strip, skelp, baror the like, which consists in rapidly reducing cold material to a stripsheet of less than half the original thickness, and then annealing the.same by a continuous method.

2. The method of making a strip sheet, from a strip, skelp, bar or thelike, which consists in rapidly reducing cold material to a strip sheetof less than half the original thickness, and then annealing the same ina short cycle.

3. The method of making a strip sheet consists in rapidly reducing coldmaterial to a strip sheet of less than half the original thickness, andthen annealing the same at a temperature of about 1300 F., in a shortcycle.

4 4. The method of making'a strip sheet from a strip, skelp, bar or thelike, which consists in rapidly reducing the material by a. small numberof heavy drafts between cold rolls to a strip sheet of less than halfthe original thickness, and then annealing the sheet by a continuousmethod. v.

5. The method of .making a strip sheet from a strip, skelp, bar .or thelike, which consists 1n rapldly reducing the materialby a plurality ofdrafts between cold rolls and then annealing the sheet by a continuousmethod. a

'- HARRY M. NAUGLE.

ARTHUR J.

